iiinova — where your digital self keeps evolving

Joshua Emrick @jjemrick.bsky.social · 06/10/2026

Check out our new pre-print! Amazing work from our lab led by @elizabithian.bsky.social and Shuhao Wan. Thanks to all co-authors. Have you ever experienced cold sensitivity of your teeth? 🦷 🧊🥶 We may have caught the culprits. A very cool...er...chilling discovery? www.biorxiv.org/content/10.6...

biorxiv.org

Myelinated mechano-nociceptors encode noxious cold and underlie hypersensitivity in pulpitis

The ability to identify dangerous temperatures is critical, but the neural basis for cold sensation remains enigmatic. By combining in vivo functional imaging with tissue-specific spatiotemporal cooli...

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Joshua Emrick @jjemrick.bsky.social · 24/03/2026

We have a newly opened search for a tenure track position in our department at UM School of Dentistry! We are excited to see your application - please note the posting for key criteria for eligibility including a PhD and BDS/DDS/DMD. apply.interfolio.com/183598

apply.interfolio.com

Apply - Interfolio {{$ctrl.$state.data.pageTitle}} - Apply - Interfolio

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Joshua Emrick @jjemrick.bsky.social · 12/03/2026

5/ Teeth, touch, and dopamine: a lesson from rodents that repetitive oral “maintenance” behaviors might be actively reinforced by the brain among mammals. Fun project with a great team! So excited to share it! 🧠🦷 @elizabithian.bsky.social @umichnews.bsky.social @science.org

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Joshua Emrick @jjemrick.bsky.social · 12/03/2026

4/ Some of these behaviors can be helpful (stress relief from chewing gum) while others can be damaging (chronic nail biting or bruxism). Understanding how oral sensory input engages reward circuits may help explain why these behaviors can be so persistent and lead us to treatments.

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Joshua Emrick @jjemrick.bsky.social · 12/03/2026

3/ This raises an interesting question: Are some human oral behaviors driven by similar sensory-reward circuits? Think about things like: • chewing gum • biting a pencil • nail biting • tooth grinding (bruxism) Many involve repetitive oral sensation that people report as oddly satisfying.

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Joshua Emrick @jjemrick.bsky.social · 12/03/2026

2/ The key idea: Gnawing depends on sensitive touch neurons around the incisors. When they “feel” gnawing they send signals to a brainstem center that 1) moves the jaw AND 2) engages midbrain dopamine neurons. Gnawing is a motivated behavior reinforced by the brain’s reward system. 🧠

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Joshua Emrick @jjemrick.bsky.social · 12/03/2026

1/ Why do rodents gnaw on everything? 🐭🪵 It’s not just because their teeth keep growing or that hard foods trim the teeth. Our new paper in Neuron shows that gnawing itself is rewarding to the brain. doi.org/10.1016/j.ne...

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Reposted by Joshua Emrick

University of Michigan News @umichnews.bsky.social · 01/08/2025

University of Michigan Literature, Science, and the Arts researchers discover a complete skin-to-brain neural circuit for temperature sensing, a finding that could help spur medical innovations such as new treatments for temperature-associated pain. t.co/52eXzMfKJX

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Reposted by Joshua Emrick

Bing Ye @byneuron.bsky.social · 31/07/2025

🧵 I’m excited to announce that the 2025 LabGym Symposium & Tutorial will be held online via Zoom on Friday, August 22, 2025. Don’t miss this opportunity to learn about cutting-edge AI-based behavioral analysis! www.lsi.umich.edu/events/2025-... 1/

lsi.umich.edu

LabGym Symposium

LabGym is a free software suite for automated video analysis and quantification of animal behavior. LabGym has now been downloaded over 55,000 times from GitHub in just about two years. The 2024 LabGy...

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Pulp fact: The tooth sensory system functions to help protect these critical, irreplaceable organs. We have additional reason to keep our dental pulp (and nerves) healthy.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Above all, we see the good in the intradental neurons. In fact, it seems that their conservation across mammals makes more sense. Tooth damage represents a fairly cataclysmic consequence for an animal in the wild (without options for dental care).

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Key experiments with our collaborator (Peng and Karin) helped control for non-specific activation of sensory neurons and helped to confirm that even activation of the intradental neuron cell bodies (that were captured with AAV transduction) produced EMG activity in the muscle that opens the jaw.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

There were many reasons why we may have failed to identify the reflex response. The anesthesia could have been too deep. The light wouldn't penetrate deeply enough. The response would only inhibit muscle contraction, not activate contraction.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We put the mouse under light isoflurane and found that its jaw made the slightest opening, very briefly, when we activated the terminals in the tooth! I was in the room where it happened (holding the fiber).

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

So, if the intradental neurons fire immediately and transiently during superficial damage, what happens when they are transiently activated? This was a critical experiment for this project. We wanted to try to see what would happen if we activation of the intradental neurons using optogenetics.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We are now considering how to use this model to explore what tooth pain further. It's now a 2nd tool (in addition to TG calcium imaging) for us to use to evaluate dental pain and analgesics.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Activation of the intradental neurons using chemogenetics gave us predictable, but key result... we found distinct behavior with features that indicated pain (corroborating previous reports). It was also stunning that the pain was on par with systemic, broad activation of nociceptors.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We were excited to test a genetic approach to delete Scn10a (which encodes the alpha-subunit of Nav1.8) because of new analgesics... did not prevent intradental responses... it seems as if newly-developed antagonists for Nav1.8 are unlikely to prevent any pain from intradental activation.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

There are some assumptions we are making in interpreting our results, but these data might hint that the molecular mechanoreceptor in question remains at-large (and represents a major unknown more broadly)...

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Many reports suggested that Piezo2 might be the major molecular mediator for dental sensation. Alas, as much as we would have loved to find the mechanoreceptor, when we knocked out Piezo2 from the intradental neurons, we still found their responses.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We also linked our work to past reports because we found that our neurons of interest also responded once the dentin had been exposed. We also used genetic and viral labeling to confirm that the HTMRs provided dentin innervation (& define their terminal morphology and receptive fields).

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Our work links intradental neurons to our latest understanding of somatosensory neurons. Our prior report predicted these neurons would be specialized high-threshold mechanoreceptors (HTMRs) based on their transcriptional expression, but these new experiments confirmed this function.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We were surprised to find that a majority responded to even slight surface damage. More responded as the damage increased.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We used calcium imaging with electrical stimulation of the tooth to find the intradental neurons without physically damaging the tooth structure. This approach was technically-challenging (mouse mouth and teeth = small), but opened the door to understanding what exactly causes them to fire.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

These findings corresponded well to what we observed in the dental clinic - dentin stimulation triggered pain. The trouble was that most of these experiments had to shave off the enamel to stimulate the dentin - so almost none of these data were collected with the tooth intact.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

We were well aware that the tooth innervation was capable of causing pain. Previously, careful ephys experiments demonstrated that many other mammals had sensory innervation within the tooth that fired to mechanical stimulation.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

TL;DR Pulp fact: The tooth sensory system functions to help protect these critical, irreplaceable organs. We have additional reason to keep our dental pulp (and nerves) healthy. See below for the deep cuts.

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Joshua Emrick @jjemrick.bsky.social · 06/08/2025

Pulp fiction: the sensory innervation of the tooth exists only to cause us pain and grief. My research group helped dispel this notion with our latest publication in Cell Reports: doi.org/10.1016/j.ce... I encourage the read...

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